Underwater drilling method



Dec. 1, 1964 FiledApril 22, 1958 A. E. WlLDE UNDERWATER DRILLING METHOD 10 Sheets-Sheet l 3g 28 FL 1 I I :4 I -j 56 ARTHUR E. W/Lfifi:

. INVENTOR.

Dec. 1, 1964 A. E. WILDE 3,

UNDERWATER DRILLING METHOD Filed April 22, 1958. 10 Sheets-Sheet 2 ARTHUR E. W/L 05,

INVENTOR. WH/M/N (i Mc MA/V//4L Afforneys fir A f/fcamf Dec. 1, 1964 A. E. WILDE 3,159,218

UNDERWATER DRILLING METHOD Filed April 22, 1958 10 Sheets-Sheet 5 S ARTHI/fif. W/LDE, INVENTOR. WHANN QZMCMA/V/GAL Z04 I Af/ornay: Far Ap I/cmn l0 Sheets-Sheet 6 Filed April 22, 1958 ARTHUR E. WM 05,

INVENTOR. WHA IVN 4:, 44 MAN/GAL Allan's fir APPIICd/l/ Dec. 1, 1964 A. E. WILDE UNDERWATER DRILLING METHOD 1o Sheets-Sheet '7 Filed April 22, 1958 2 m" 4 W M W W m E .6m n N... 3 U W 7 W Ar m M W4 Dec. 1, 1964 A. E. WILDE UNDERWATER DRILLING METHOD Filed April 22, 1958 Fig 10 Sheets-Sheet 1O ARTHUR E. W/[ 0 INVENTOR.

United States Patent 3,159,218 UNDERWATER DRILLE'JG METHGD Arthur E. Wilde, Santa Ana, (Ialitl, assignor to Shafier Tool Works, Bren, Calif., a corporation of California Filed Apr. 22, 35%, Ser. No. 730,172 4 Claims. (Cl. 166-46) This invention relates to a method for drilling bore holes in the earth and relates more particularly to apparatus and method for underwater drilling of such holes in the production of wells such as oil wells and the like.

While the invention has particular utility in connection with offshore drilling of oil wells and the like, and is herein shown and described in connection therewith, it is to be understood that its utility is not limited thereto.

In the prior art, wells have been drilled into submarine formations in relatively shallow water protected to some extent at least by reefs or the like. Also, in some prior operations various types of structures have been employed to support the equipment required to drill the well, including platforms and the like.

Where the water is shallow, the problems of offshore or underwater drilling are not difiicult of solution However, there are many difiicult problems involved in drilling in deep water and in certain localities such as the I Pacific Coast for example, the waters are relatively deep even a short distance from shore.

When the drilling is in such relatively deep water, a floating platform is used and comprises a specially equipped boat or barge which must be anchored as securely as possible. Various problems are encountered from the initial drilling operations to the completion of the well and the installation of the production equipment.

It is, therefore, an object of the present invention to provide means and method for solving these problems.

In the drilling operations, the well head and blowout preventer equipment should be mounted as close to the underwater fioor as possible and it is another object of the invention to provide means located close to the ocean floor for remotely connecting the various equipment to the casing or disconnecting said equipment from said casing.

It is another object of the invention to provide improved means and method for initiating the drilling operations.

It is a further object of the invention to provide improved means for effecting the cementing operations.

It is a still further object of the invention to provide effective means for supporting one or more strings of tubing.

It is another object of the invention to provide means for releasably securing the tubing hangers.

It is a further object of the invention to provide means and method for lowering and connecting various tools to the mandrel at the upper end of the installed casing.

It is still another object of the invention to provide means and method for raising and lowering various tools.

The characteristics and advantages of the invention are further sufiiciently referred to in connection with the following detailed description of the accompanying drawings which represent a preferred embodiment of the method and apparatus or means. After considering this example, skilled persons will understand that many variations may be made without departing from the principles disclosed and I contemplate the employment of any structures, arrangements or modes of operation that are properly within the scope of the appended claims.

Referring to the drawings:

FIG. 1 is a perspective undersea view of a boat used in connection with the present invention;

FIG. 2 is a side view, partially in section of the anchor in place and the drill pipe with the drill just beginning to drill into the formation;

FIG. 3 is a sectional view of the conductor with the landing base and bucket and swabs for cementing, and cement guide;

FIG. 3A is a sectional view of the cable bucket showing the J slot therein;

FIG. 4 is a side elevation, partially in section, showing the drilling and setting packer and drilling string stabbed therethrough;

FIG. 5 is a side elevation, partially in section, of the equipment used in the fifth stage of the drilling operat1ons;

FIG. 6 is a side elevation, partially in section, of the equipment used in the sixth stage of the drilling operations;

FIG. 7 is a side elevation, partly in section, of the succeeding or seventh stage of the drilling procedure;

FIG. 8 is a side view, partially in section, of the last or eighth stage of the drilling operations;

FIG. 9 is a side view, partially in section, of the upper end of the well head equipment fully installed;

FIG. 10 is a side view, partially in section, of the lower portion of the well head equipment installed;

P16. 11 is a side view of the setting tool for bit guide with the bit guide attached thereto;

FIG. 12 is a similar view showing the bit guide installed and the setting tool drawn upwardly therefrom;

FIG. 13 is a fragmentary longitudinal section of a portion of the well head equipment showing the bit guide in position; and

FIG. 14 is a side view of a final release rod assembly.

Referring to FIG. 1, underwater drilling operations are carried out from a floating support or boat, as disclosed in the Gibson et al. application, Serial No. 627,250, for Method and Apparatus for Ofishore Drilling, filed December 10, 1956. The boat, indicated generally at 25, is anchored, by cables 26, over the formation into which the well is to be drilled. Boat is provided with the usual machinery and equipment for drilling wells and includes a derrick 27 disposed over an opening or well 28 which extends vertically through the ship and through which equipment is raised and lowered and the drilling operations carried out.

The boat is provided with the various equipment required for drilling operations and in FIGS. 1 and 2 there is shown a drill string 30 having a rotary drill at the lower end thereof, indicated schematically at 31.

Preparatory to the drilling operation itself, an anchor is lowered onto the surface 36 of the formation 37 into which the well is to be drilled or bored. The anchor is of substantial weight and is shown as comprising a reinforced block of concrete 38 having a relatively large central opening 39 therethrough and also having a downwardly extending peripheral flange 40 which penetrates the surface of the formation. The anchor remains in position because of its weight and is held from shifting by reason of said Weight and also the flange 40.

Guide cables 42 have their lower ends secured by any suitable well-known clamp means to respective pins 43 mounted in the upper ends of members 44 projecting above the top surface of the anchor. The members 44 have their lower parts securely embedded in the anchor 33 or otherwise secured thereto. The cables 42 extend upwardly through the well 28 and are attached at their upper ends to torque converters which maintain said cables taut as described in the above referred to Gibson et al. application, Serial No. 627,250.

The vertical opening 39 through the anchor 35 is of substantial cross sectional area and is of substantially casing.

After the anchor 35 has been loweredon to the surface 36 of the formation 37 by means of the guide cables 42,

the drill string 3% is assembled with the drill 311 at the 7 lower end and the latter is guided downwardly by means of a bit guide, indicated generally at b. The bit guide includes a ring 51 which is slidable on the drill collar 52 which carries the bit 3} at its lower end. Bit guide 50 also includes a pair of oppositely extending arms53 :having tubular cable receiving elements 54- in which the guide cables 42 are slidable. During the bit lowering procedure, the ring Sirests on the shoulder 56 of the bit 31. When the bit enters the opening 39,.t-he elements 54 contact the ears 44 and thereafter the'collar 52 slides downwardly through the ring 51. As the drilling continues, the drill string, of course, continues to slide through said ring 51. The first portion 57 of the well is bored and it is to be noted that the bit guide 50 guides the bit substantially axially through the opening 39.

After the bore portion 57 has been drilled to the desired depth, the drill string 3% and bit 31 are removed and as the bit rises above the surface of the anchor 35, it picks up the ring 51 and is guided to the boat.

" Next the casing 63, FIG. 3, is assembled and a manila rope tied to the lower end, the free end portions of the rope then being tied to the respective guide cables dz with a loop 62 of sufficient size to permit ready sliding thereof r I I V V latter stabilizes the lower end of the drill string Elias it on said cables. into the bore 57.

At the' 'iipper end of the casing 6d, there is a landing base assembly which comprises a plate 63 of larger size than the opening 39 in the anchor 35. Plate 63 is connectcd to the upper end of a. tubular part 64 a little larger The casing'is lowered and thus guided than the casing tl. Plate 63 may be welded to the part 64 or otherwise secured thereto and there are reinforcing plates 65 beneath the plate 63 and the tubular part 6 V Plates 65 are welded or other-wise secured to the plate 63 and tubular part 64 and said plates 65 are arranged vertically. The lower end of the tubular part 6 is connected to the upper end of the casing 66 by any suitable means such as screw threads or by welding. As shown, there is an enlarged diameter part .66 in the lower end of the tu bular part ed in which is received an upper end portion of the casing 68. The parts are then welded together. Spaced upwardly of the upper end of casing 6d are a plurality of vent openings 67 in the tubular part 64 and drill Hi2 at the lower end of said collar.

as best shown in FIG. 3A. 'When pins Ed'reach the lower end of the vertical portion 8b of the J-slot 88, the drill string and member 83 are rotated to cause the pins 86 to.

move into and through the horizontal part 9% of said slot and into the inner vertical portion 91 and thence tothe lower end of said inner vertical portion. When well pressure is exerted upwardly on the swabs 8d, the pins 86 will move into the upper end of the slot portion 91 and the swabs thus held securely in the well. The member $3 has a plurality of vertically arranged annularly spaced fins 93 whichare secured to the sub 82 and also to said member for reinforcement purposes. It is'to be noted that the lower ends of the fins 93 are rounded to facilitate entrance thereof into the upper end of the tubular part 64.

When the member 83 is disposed as shown in FIG. 3, the swabs 8b are disposed somewhat below the vent openbags 67. Cement then is introduced into the well through the drill string 3%} and passes upwardly in the annulus 35 about the casing. The cement is indicated at and it is.

moved, It is to be noted that when lowering the swab 8t) ,into the well, aguide arrangement such as shown at 59, FIG; 1, may be used to align said swabs with the bucket 79 and open upper end of the tubular part 6 5. 'As

the swabs are removed, they pick up the guide and the i is raised to. the ship.

The next step in the drilling procedure is the drilling of a reduced diameter bore 1%, FIG. 4, for the surface pipe, saidbore res being drilled toany desired depth.

Preparatory to drilling the bore ran, the drill string is,

prepared with a drill collar 19} at the lower end and a Above said collar there is disposed a drilling and setting packer assembly which includes a tubular body we? at the lowerend of which is attached by screw threads or the like, an inflatable packer, indicated generally at 1416. T his packer is of known type and includes an upper cylindricalmember Mi? which is of somewhat smaller external diameter thanthe internal diameter of the tubular part dd and cylindrical member id? is an enlarged diameter part having a downwardly facing seat see. The cylindricalmernher it}? hasa passage 139' therethrough and depending I I from said member is a reduced diameter portion llll on to which is secured a cable bucket that is tunnel shaped I with the large open end facing upwardly. There are a pair of arms 73 which extend oppositely of each other from the bucket and the part 69 of the tubular part 64 i and have at their outer'free ends tubular sliding elements For the cementing operation, there is provided a pair of swabs attached in the usual manner'to the lowerend of a drill pipe section 81. The upper end of the pipe sec tion 811s threadably or otherwise secured to the lower end of a sub 82 connected atits upper end to the lower end of the drill string 3%. The sub 82 has secured thereto a' cylindrical member 83 having ;a flange '84 at its upper inwardly inclined to for-ma seat 85. The external diam eter of -the member 83 is such as to readily but snugly enter into the upper ends ofthe tubular part 164-. Memwhich is dispose'd'a seal element 112; of suitable resilient recess 114 which provides a fluid pressure chamber and 7 said seal is secured onto the reduced diameter portion llllby a nut 115 which is threadably attached to the lower I end of said portion llll. Chamber lid is connected to a suitable source of hydraulic pressure by a-conduit 116 which is connected to a passage through the member M7,

end, the lower end of said flange being downwardly and O ing a rotatable seal therein which is engageable with the drill string. Examplesof such drilling heads are disclosed in the above referred toGibson et a1. applicatiomSerial No. 627,250. There are oppositely extendingrarms 12.2"

on the drilling head 120 and said arms are provided at their outer ends with tubular sliding elements 123 for slidable reception therein of the guide cables 42. I

'When the drill string is initially lowered from the boat or floating supporgthe lower endofthe inflatable packer ber 83 has a pair of oppositely arranged pins 86 for entry into-the upper open ends 87 of J-slots 88 arranged dialbs rests upon the shoulder 12d of the bit M2 inasmuch as the passage through said packer is of smaller internal diameter than the external diameterjot the collar idl.

as the latter is lowered into the well and the guide arrangement, including the arms 122 and elements 123, guide the bit and packer into the housing 76 and thence into the upper end of the part 64 of the landing base assembly.

When the seat 1198 of the inflatable packer 1116 seats on the shoulder 63 of the tubular part 64, the drill bit 162 continues on downwardly but the above referred to packer, body and drill head assembly is supported in the position shown in FIG. 4. Hydraulic pressure is then supplied to the chamber 114 to expand the seal 112 into tight sealing engagement with the interior of the conductor pipe or casing 61 and the tubular part 6 1. This prevents drilling fluid and the like from escaping upwardly into the Water past said packer. Such drilling fluid however flows upwardly between the drill string and the wall of the interior passage of the packer 106, the passage through the tubular body 1135 and into the head 120. The rotatable seal in the head provides a seal against escape of fluid past the drill string and into the water. The drilling fluid leaves the head by means of the valve arrangement indicated generally at 126 which is provided with a body 127 and a discharge or outlet conduit 12%. Any suitable arrangement may be employed for taking off the fluid, there being devices of this character on the market. For

xample, the Cameron Flex-Seal mud valve may be used.

After the packer 1116 has been inflated into sealing engagement with the interior of the well casing, the drilling of the bore 1% proceeds. When this bore has been drilled to the desired depth, it is raised by means of the drill string 31} which includes a bumper sub 129. The pressure to the packer having been relieved so that the seal 112 returns to its normal external diameter, the assembly of said packer 1116, body 1115 and head 12% will be raised by said drill string when the shoulder 124 of the'bit 1112 engages the lower end of said packer.

Reference is now made to FIG. 5 for the fifth stage in the drilling procedure. A casing or surface pipe 135 is assembled and lowered into the bore 160. The lower end of the casing 135 is guided downwardly on the cables 42 by means of the manila rope arrangement described above, the loops of said rope being shown at 1$7 in FIG. 5. At the upper end of said casing or surface pipe, there is provided a safety release joint of suitable character, indicated generally at 136, interior details being shown in FIGS. 9 and 10. Joints of this character are also disclosed in the Waggener application, Serial No. 390,321, for Torque Releasing, Safety Joint for Well Tool Strings, filed No vember 5, 1953, the Waggener application, Serial No. 605,241 for Release Casing Safety Joint for Well Tool Strings, filed August 21, 1956 and the McClintock et al. application, Serial No. 648,293 for Hydraulic Release Safety Tool Joint, filed March 25, 1957. This safety re lease joint includes a tubular mandrel 138 of such external diameter as to be slidably received in the portion of the tubular part 64 above the shoulder 68 thereof, said mandrel having an inwardly and downwardly inclined seat 139 adapted to seat on said shoulder 68, the lower end of said mandrel being connected by screw threads or other suitable means to the upper end of the casing 135 and the latter is supported thereby. The mandrel also has a depending portion 1 11) of somewhat reduced diameter to be received within the portion of the tubular part 64- below said shoulder 68 thereof. The part 14% terminates above the openings 67 and there is a depending reduced diameter part 142 to which is threadably or otherwise connected a collar 143 which in turn is threadably or otherwise connected to the upper end of the casing 135. The collar 143 is of'sornewhat smaller external diameter than the internal diameter of the tubular part 64, to permit passage d of fluid upwardly between said part 143 and the interior of the part 64, and there is an annular space or recess 144 between the lower end of the part of the mandrel and the upper end of the collar 143, with which space 144 the ports or openings 67 communicate.

The release joint 136 also includes a barrel unit, indicated generally at 1 15 (FIGS. 5 to 10 and 13). Referring more particulanly to FIGS. 9 and 10, the barrel unit includes a tubular barrel 146 having a tubular sub 1 17 connected to the upper end, the latter being connected to the bottom of a dual blowout preventer, indicated generally at 150, FIG. 5.

The mandrel 1313 has an upwardly extending reduced diameter portion 151 slidably receivable in the lower end portion of the barrel 146 and provided with helical or inclined recesses 152 for reception of lugs 153 on the inner side of the barrel. There is also a key sleeve 154 slidable within the barrel and urged to a predetermined lower position by a spring 155. When thelugs 153 are in the recesses 152, keys 156 on the lower end of the tiey sleeve 154 enter key recesses 157 to prevent the lugs 153 from moving upwardly and outwardly of the recesses 152. Thus, the barrel unit is securely held on the mandrel but may be released therefrom by a releasing tool as described in said Waggoner application, Serial No. 605,241.

Referring to FIG. 5, there is shown a spool connector 161 connected to the upper end of the dual blowout preventer in the usual manner. The connector 161 has a plurality of tapped openings therein whereby outlet valves 161 may be connected with the interior passage of said connector and also valves 162 may be connected with said passage. The upper end of the spool connector 1611 is connected in the usual way to a blowout preventer in dicated at 164. The blowout preventer 164 may be of any suitable type, one such type being disclosed in the above referred to Gibson et al. application, Serial No. 627,250 and manufactured by the Hydril Company and identified as their Type G-K. Secured to the upper end of the blowout pi'eventer 164 is a submarine drilling head 165 also disclosed in the above referred to Gibson et al. application, Serial No. 627,250 and in the Gibson et a1. application, Serial No. 670,428 for a Drilling Head, filed July 8, 1957. Attached to the upper end of the rotary submarine drilling head 165 is secured, by any suitable well-known means, a cable bucket or funnel 166 similar to the cable bucket 71 Arms 167 on the bucket have cable receiving elements 168 for slidable reception of said cables. There are a pair of support rods 169 having end members 171 and 171. The members 176 are pivotally connected at 172 to the arms 167 and the members 171 are pivotally connected at 173 to bosses 174 on the blowout preventer 151 A turnbuckle 175 is provided for each support rod for adjusting the length thereof.

The blowout preventer 150 is of well-known type and includes upper and lower rams 176 and 177 respectively. Rams 17 6 are shown in the closedposition wherein they are received within an external peripheral groove in a tool 78. The upper end of tool 178 is connected to the adjacent end of the drill string 31) and the lower end of said tool is connected to a section of drill pipe 181 having a pair of swabs 86 attached adjacent the lower end thereof and spaced longitudinally apart.

Lowering of the equipment shown in FIG. 5 is accomplished in the manner described in the above referred to Gibson et al. application, Serial No. 627,250. The rams 176 of the preventer 151 are closed into the groove in tool 178 to thereby connect said preventerto said tool and hence to the string 31). The equipment above the blowout preventer 159 is, of course, carried thereby as well as the safety release joint .136 and the casing 135. When the equipment is in the position shown in FIG. 5, with the shoulder 139 of the release joint 136 seated on the shoulder 68, the rams 176 are-opened by supplying pres sure fluid through one of'the conduits 183 tothe hydraulic actuating mechanism of said rams. As dual hy- .scribetheir constructionin detail.

I 7 With the equipment positioned as shown in FIG. 5,

draulic blow-out preventers such'as shown at 15b are known in the art, it is believed that it is-unnecessaryto decement is supplied through the drill string and discharged therefrom below the swabs 8d. The cement passes down- ,wardlyin thersurface pipe-135 and upwardly about the same in'the bore 1%. Cement also passes upwardly be tween the exterior of said surface pipe and the interior of the conduct-or pipe where these pipes are .telescopcd togather at the upper end. The cement flows upwardly into the recess 144 and out of the openings Tinto the upper end of the bore 57. r

After the cementing operation has been completed, the

I swabs are raisedand the stripper sleeve assembly 190,

FIG. 6, of the rotary drilling head 165 is released bysupplying hydraulic pressure through one' of the conduits 191connecting'the drilling head .165 with a source of suitable hydraulic pressure. As described in the Gibson et a1. application, SerialNo. 670,428, the stripper sleeve assembly is released by hydraulic latching and releasing means. As the swabs are raised, they engage and pick up thereleased stripper sleeveassembly which is carried to the ship.

a The sixthstage, FIG. 6, is the drilling of a further re" duced diameter bore 289 from the lower end of thebore 199, said bore 200' being drilled to any desired'depth.

Preparatory to drilling bore'2ll l, the drill string'is as sembled with a bumper sub 262 at the lower end thereof and adrill collar 203 at the lower end of said bumper sub with the bit/201' at the lower endfof said collar.

The stripper sleeve 1% is disposed on the string and is supported on the shoulder 204' of the bit as the latter is lowered. Above the stripper sleeve is disposed a guide,

indicated generally at 205, comprising a ring 2&6 having a V a central opening sufiiciently large-to slide on the bumper I, sub-262 and drill collar 203. The ring is'provided-with outwardly extending arms 297 which carry the cable receiving element 298 in which the cables 42 are slidably disposed. 'As the bit is lowered throughthe submarine drilling head 165, blowout preventer 150 and down into the well, the stripper sleeve assembly enters the head 165' seats therein. Thereafter, hydraulic pressure is sup plied through the appropriate conduit 1% to etfectlocking of the sleeve in the head. As in the case'of the head 12!); there is a'seal that engages the drill string and is rotatable-in the head so as to rotate with said string during the drilling operations. Drilling fluid is circulated 160 and the drilling head 165, said blowout preventer 164 being omitted from the assembly shown in FIG. 6. After the drilling of the bore 200 to the desired depth,

5 the drill is removed, the stripper sleeve assembly being released from the drilling heel (116$bysupplying'hydrau- .lic pressure to the releasable latching mechanism-of said head'165 and the stripper sleeve assembly and guide-205 are carried upwardly on the-bit 201. a p

' A casing string 219, FIG. 7, of the proper size for the bore 200 isthen assembledand'lowered into the well. The lower end of the casing string 210 is providedwith a rope guide arrangement such as'described hereinabove' in connection, with-the casing 60 a'ndfcasing' 135. The rope, arrangement'guides the lower end of the easing into the well; At the'upper end' of the casing 210 there is connected, by means, of a collar 211, a self-locking'tubing or casing" hanger, indicated generally at 214, FIG. 10, 'which is' disclosed in the Gibson application, Serial No. 5O8615ffor Self-Locking Tubing'I-ianger, filed May 16,

with latch means which includes a plurality of annularl'y arranged resilient fingers 217 having free end portions" 218 which are 'releasably received inan internal annular groove 219 in said mandrel 138i]: upwardly spaced relation to the shoulder 216 of said mandrel. The upper end of the automatic tubing hanger 214 is provided with an upwardly extending externally threaded portion 220 H on which is screwed an adapter 221 which is provided at the upper end with a socket 222 having left-handed j release threads 223. Within the adapter 221 there is an annular shoulder 224 and an'internal groove 2 spaced 7 upwardly therefrom. ,A left-hand back oil too] 226 is.

provided at the lower end of the string of pipe used for. a lowering the casingzltl with its automatic hanger 214 p and adapter 221. When the casing 210 has been installed and cemented in, the back off tool is removed in th usual manner and raised to the boat.

This "is followed by'the seventh stage of the drilling operations, a further reduced diameter bore 250 being drilled from the lower endof the bore 2%, thebore 230 being drilledwith equipment and according to the procedure, described herein above. After bore 236* has been 'drilledio'the desired depth, the drilling-equipment is removed to'the boat. I

In the eighth stage'a casing string 235 is assembled and the lower end thereof provided with a rope guide arrangement such as described above in connection with other. casing strings, said rope guide means guidingthe lower end of the casing 235mm the bucket 70 and upper end of the well. Thev upper end of the casing 235 is connected by a collar 236 to a tubing hanger 237 of proper size, said tubing hanger 237 having an external annular seat 238 which tapers downwardly and inwardly ;and seats on the shoulder 224 of the adapter 221. The. tubing hanger 231 includes the latch arrangement haying fingers 217a with projections 218a which are releas ably received withinthe annular groove 225 ofsaid adapter 221. i

The body portion 240 of ceiving recesses 153 and key slots 157.for reception of th'roughthe well during the drilling operation for the bore 7 {280' as in the case of the drilling operation for drilling the bore 100. Also, it is to be understood that a blowout preventer 164 is interposed between the spool connector I well head, a casing safetyjjoint bit guide is used,'said' guide being shownin FIGS.'11 and 12. comprises a tubular body 250 adapted to be received' keys 156 of key sleeve 154 whichis slidablymounted in the barrel 2420f the barrel unit, indicated generally at 243; The barrelunit 2431s, of course, connected to a pipestring extending-upwardly to theboat. When the casing 235' has bei1:1QWeI6d into position, at which time s the seat 238 of the hanger 2371s seated on the shoulder 224, the casing 235 is cemented in and the barrel unit V then removed-from. the mandrel portion of said safety release joint.

In order to prevent damage to'the drill or parts of the The bit guide 'on theupperend portion 251 of a mandrel shank 151,

1955. "This tubingrhanger has an external annular seat;

2 15. that tapers downwardly and'inwar'dly'and seats on an internalannular shoulder 21am. the mandrel 138 of the safety release joint 1 The tubing hanger is provided the lower end of said body resting on shoulder 2520f the mandrel. At the upper end ot the body the bit guide flares outwardly and upwardly at 253 and at the upper end'of the flared portion 253 there is an annular flange 254. Within the flange 254 are J-slots which are arranged at diametrically opposite sidesandare adapted toreceive respective pins 255 of a bit guide setting tool, indicated string.

the hanger 237 alsoserves as the mandrel of a'safety release jointindicated genera ally at 241, said body portion 24% havingashank-which I extends upwardly and is provided with thespiral lugre The bitguide: is attached in the Sant na Br ws),

in FIG. 11. In attaching the bit guide, the pins 255 are inserted in the open ends of the vertical portion 262 of the J-slots and when said pins are at the lower ends thereof, the bit guide is rotated so that said pins pass through the horizontal portions 263 of said slots. When the pins enter the inner vertical portions 264 of said slots, the guide is lowered so that said pins enter the upper ends of said portions 264 which upper ends are above the horizontal portions 263 so that the bit guide will be locked on the setting tool. The bit guide should be attached by hand to prevent shearing off of the pins 255.

The assembly of bit guide and setting tool is turned to the left by hand and lowered so that the bit guide is disposed on the upper end of the mandrel as described above. As the unit is lowered over the mandrel, it will continue to be free turning to the left until the keys 250a in the bit guide body 250 engage with the key slots on the safety joint mandrel, at which time a build-up in torque resistance will indicate such engagement. It will be noted that the pins 255 have entered the lower portions of the vertical slot parts 264 which are below the horizontal parts 263.

At this point the setting tool is ready to be detached from the bit guide. Left-hand torque is again applied by using hand tongs or the like. The unit is raised slowly while holding the left-hand torque and the pins 255 of the setting tool will rotate into the horizontal portions of the J-slots of the bit guide until said pins reach the vertical portions 262 of said slots whereupon the setting tool will separate from the bit guide.

The bit guide may be readily removed by reattachment of the setting tool so that the pins 255 are inserted into the J-slots and moved to the position shown in FIG. 11 whereat said pins are in the upper ends of the portions 264 of said slots. The bit guide may then be removed from the mandrel and the assembly raised to the surface or to the boat. Bit guides of suitable size may be used in the various drilling stages to protect the equipment.

Preparatory to installing the production equipment, the dual blowout preventer 150 and the equipment above same are removed by disconnecting the barrel unit 146 from the mandrel 138 of the release joint 136. In order to effect release of said barrel unit, a special releasing tool is used in view of the fact that the upper end of the mandrel of the release joint 241 extends upwardly of the plane of the internal annular groove 270 in the key sleeve 271 of barrel unit 146.

The releasing tool for effecting release of the barrel unit 146 from its mandrel 138 is shown in FIG. 14. The device comprises a cylindrical body 275 which is open at the lower end and the cylindrical interior 276 of said body is adapted to slide over the above referred to mandrel. Adjacent the lower end of the body 276 are a plurality of vertically arranged annularly spaced openings 277 in which fingers 278 respectively are received. These fingers are pivoted at 279 adjacent their lower ends and the upper ends are urged outwardly by leaf springs 28%) secured to the inner side of the body 275 by rivets 281 or the like. Each finger is provided with a leaf spring 289 and the upper ends 282 of said fingers are adapted to engage the shoulder 284 at the upper end of the recess 27%. The body 275 is connected to a sub 285 which, in turn, is connected to a tubular portion 286, the latter being connected to an axially arranged tubular part 287 having at its upper end radial vanes 288 which serve to stabilize the tool and maintain it in proper axial arrangement within the barrel unit 246. The upper end of the tubular part 287 is provided with a collar 288a for connection with a string of pipes leading to the ship. When the tool has been lowered into position so that when the fingers 278 engage the shoulder 284, the key sleeve 271 will be pulled upwardly to remove the keys 156 from their slots 157. The lugs 153 will then slide out of their grooves 152 and the barrel unit will thereupon be separated from the mandrel.

In raising the dual blowout preventer and the equipment supported thereby the tool 178 is again employed and the rams 176 close into the groove provided in said tool. The entire assembly may then be raised by means of the drill string 30.

It is to be noted that removal of the blowout preventer and the equipment supported thereby is effected in the manner described in the above referred to Gibson et al. application, Serial No. 627,250. In said Gibson application, the releasing tool for the barrel unit is of a different type from that shown in FIG. 14. However, the general mode of operation of the two arrangements is substantially the same.

The releasing tool is raised with the barrel unit, the blowout preventer 150 and the equipment supported thereby and is removed from the barrel after said barrel, blowout'preventer and equipment has been raised to the ship.

After the preventer 150 and the other equipment has been raised, suitable means is attached to the last inserted casing of the well to conduct fluid therefrom to a point of disposal or collection.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it is thought that it will be apparent that various changes may be made in the form, construction and arrangement of the parts of the invention and the steps of the method thereof, without departing from the spirit and scope of said invention or sacrificing all of its material advantages.

I claim:

1. A method for drilling into an underwater formation, including the steps of: depositing an anchor on the surface of the formation, said anchor having an opening therethrough and having guide means attached to the anchor and extending to a surface support; assembling a pipe string on the support; securing the lower end of the pipe string to the guide means; lowering the pipe string along the guide means through the hole in the anchor to the surface of the formation; drilling a hole in the formation under the anchor; removing from said hole the pipe string; assembling a conductor casing; attaching a breakable link between the lower end of the casing and the guide means; lowering the casing to the surface of the formation; breaking the link; lowering the casing into the hole and cementing the casing in the hole.

2. A method for drilling into an underwater formation, including the steps of: depositing an anchor on the surface of the formation; said anchor having an opening therethrough and having guide means attached to the anchor and extending to a surface support; assembling a pipe string on the support; securing the lower end of the pipe string to the guide means; lowering the pipe string along the guide means through the hole in the anchor to the surface of the formation; drilling a hole in the formation under the anchor; removing from said hole the .pipe string; assembling a conductor casing; attaching a breakable link between the lower end of the casing and the guide means; lowering the casing to the surface of the formation; breaking the link; lowering the casing into the hole; cementing the casing in the hole, guiding tools downwardly along the guide means into the hole; drilling the hole deeper; installing additional casing strings in the holes and securing a conduit to the last installed casing for conducting fluid therefrom.

3. A method for drilling into an underwater formation, including the steps of: depositing an anchor on the surface of the formation; said anchor having an opening therethrough and having guide means attached to the anchor and extending to a surface support; assembling a pipe string on the support; securing the lower end of the pipe string to the guide means; lowering the pipe string along the guide means through the hole in the anchor to the surface of the formation; drilling a hole in the formation under the anchor; removing from surface ofthe formation; breaking the link; lowering the casing into the hole; cementing the casing in the hole; drilling the hole deeper; inserting additional casing strings in the preceding casing; suspending said additional casing on the preceding casing and securing'a conduit to the last installed casing for conducting fluid therefrom.

4. A method for drilling into an'underwater formation, including the steps of: depositing an anchor on the surface of the formation; said anchor having an opening therethrough and having guide means attached to the anchor and extending to a surface support; assembling a pipe string on thesupport; securing the lower end of the pipe string to the guide-means; lowering the pipe string along the guide means throughthe hole in the anchor to the surface of the formation; drilling a hole in the formation under the anchor; removing from said hole the pipe string; assembling a conductor casing; attaching a breakable link between the lower end of thecasing and the guide means; lowering the casing to the surface of the formation; breaking the link; lowering the easing into thehole; cementing the casing in the hole, assembling adrill'string on the support; attachinga breakable link' between the lower end of the string and the guide means,

lowering the string to the surface of the formationgf breaking the link; lowering the string into the hole; drill ing the hole deeper and removing the drill string from the hole.

References Cited in the file of this patent UNITED STATES PATENTS 866,005 Dennis Sept. 17, 1907 1,668,559 Hansen May'8, 1928 1,898,649 Wheeler et al. Peh. 21, 1933 2,099,048 Burns et a1 Nov. 16, 1937 2,102,555 Dyer 'Dec. 1 4, 1937 2,160,472 I Cizek May 30, 1939 2,239,531 Laurie Apr; 22, 1941 2,358,677 Yancey Sept, 19, 1944 r 2,512,783 Tucker June 27, 1950 2,613,983 Knudsen ;0ct. 14,1952 2,622,404 Rice 'Dec. 23, 1952 2,736,384 Potts Feb. 28, 1956' 2,783,027 Gilbert Feb. 26, 1957 2,808,229 Bauer et al Oct. 1, 1957 2,891,770 Bauer et a1 June 23, 1959 2,909,359

Bauer et al. -2. Oct. 20, 1959 

1. A METHOD FOR DRILLING INTO AN UNDERWATER FORMATION, INCLUDING THE STEPS OF: DEPOSITING AN ANCHOR ON THE SURFACE OF THE FORMATION, SAID ANCHOR HAVING AN OPENING THERETHROUGH AND HAVING GUIDE MEANS ATTACHED TO THE ANCHOR AND EXTENDING TO A SURFACE SUPPORT; ASSEMBLING A PIPE STRING ON THE SUPPORT; SECURING THE LOWER END OF THE PIPE STRING TO THE GUIDE MEANS; LOWERING THE PIPE STRING ALONG THE GUIDE MEANS THROUGH THE HOLE IN THE ANCHOR TO THE SURFACE OF THE FORMATION; DRILLING A HOLE IN THE FORMATION UNDER THE ANCHOR; REMOVING FROM SAID HOLE THE PIPE STRING; ASSEMBLING A CONDUCTOR CASING; ATTACHING A BREAKABLE LINK BETWEEN THE LOWER END OF THE CASING AND THE GUIDE MEANS; LOWERING THE CASING TO THE SURFACE OF THE FORMATION; BREAKING THE LINK; LOWERING THE CASING INTO THE HOLE AND CEMENTING THE CASING IN THE HOLE. 